The present invention provides a new data communication method and apparatus in which an intentional disturbance is applied to data to be transmitted, by using a neural network, thereby preventing the interception of the data during the data transmission. With the progress of the communication network technology in the future, the amount of communication data to be transmitted and received will become extremely large, and specifically, the transmission and reception of image data will become more and more important Since image data has a data structure which can be clearly understood at a glance, there is a possibility that the secrecy will be easily breached by the interception of such data in transmission. Therefore, particularly, upon transmission and reception of image data, it is necessary to enable the image data to be received by only a partner to whom a sender wants to send the data by using some disturbing means to establish a security in the transmitted data.
In a conventional apparatus, such as a facsimile apparatus, image data is transmitted and received in accordance with a standardized format based on a sequential raster scan of the data . Therefore, the image data to be transmitted has an intrinsic data structure which can be easily monitored by everyone. On the other hand, there is also a case where the image data is transmitted to a different partner due to an erroneous telephone call connection, thus resulting in breach of secrecy due to leaks. On the other hand, in ordinary data communication as well, for instance, the standard data encryption method as shown in DES (Data Encryption Standard: FIPS PUB 46, NBS, U.S. Dept., Commerce, 1977-1) and various other methods based on an open-key type encryption technique have been examined, and parts of these methods and techniques have already been put into practical use. However, in order to apply them to the transmission image data, since the encrypting and decrypting means in those methods are so complicated, they are not yet widely put into practical use especially for image data transmission.